Balance based mixing control device and control method

摘要

The invention relates to the application of balance based control in a fieldbus environment. Examples of cases where control is preferably based on balance calculations are mixing of liquids of different temperatures to form a stream having a desired temperature and flow rate, and the mixing of two solutions to provide a desired concentration. A typical embodiment is consistency control in the pulp industry. The use of balances in a fieldbus environment according to the invention is particularly advantageous as all required measurements are available. Further, an improved method for updating the ratio factor in the balance based control is disclosed.